Merge branch 'master' into tobits-deprecation

41 files changed, 1165 insertions, 308 deletions

diff --git a/src/test/scala/chiselTests/AnnotatingExample.scala b/src/test/scala/chiselTests/AnnotatingExample.scala
new file mode 100644
index 00000000..c84edf86
--- /dev/null
+++ b/src/test/scala/chiselTests/AnnotatingExample.scala
@@ -0,0 +1,145 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import chisel3._
+import chisel3.core.Module
+import chisel3.internal.InstanceId
+import chisel3.testers.BasicTester
+import org.scalatest._
+
+import scala.util.DynamicVariable
+
+//scalastyle:off magic.number
+
+/**
+  * This Spec file illustrates use of Donggyu's component name API, it currently only
+  * uses three methods .signalName, .parentModName and .pathName
+  *
+  * This is also an illustration of how to implement an annotation system in chisel3
+  * A local (my) Driver and Builder are created to provide thread-local access to
+  * an annotation map, and then a post elaboration annotation processor can resolve
+  * the keys and could serialize the annotations to a file for use by firrtl passes
+  */
+
+class SomeSubMod(param1: Int, param2: Int) extends Module {
+  val io = new Bundle {
+    val in = UInt(INPUT, 16)
+    val out = SInt(OUTPUT, 32)
+  }
+  val annotate = MyBuilder.myDynamicContext.annotationMap
+
+  annotate(AnnotationKey(this, JustThisRef))   = s"SomeSubMod($param1, $param2)"
+  annotate(AnnotationKey(io.in, AllRefs))      = "sub mod io.in"
+  annotate(AnnotationKey(io.out, JustThisRef)) = "sub mod io.out"
+}
+
+class AnnotatingExample extends Module {
+  val io = new Bundle {
+    val a  = UInt(INPUT, 32)
+    val b  = UInt(INPUT, 32)
+    val e  = Bool(INPUT)
+    val z  = UInt(OUTPUT, 32)
+    val v  = Bool(OUTPUT)
+    val bun = new Bundle {
+      val nested_1 = UInt(INPUT, 12)
+      val nested_2 = Bool(OUTPUT)
+    }
+  }
+  val x = Reg(UInt(width = 32))
+  val y = Reg(UInt(width = 32))
+
+  val subModule1 = Module(new SomeSubMod(1, 2))
+  val subModule2 = Module(new SomeSubMod(3, 4))
+
+
+  val annotate = MyBuilder.myDynamicContext.annotationMap
+
+  annotate(AnnotationKey(subModule2, AllRefs))     = s"SomeSubMod was used"
+
+  annotate(AnnotationKey(x, JustThisRef)) = "I am register X"
+  annotate(AnnotationKey(y, AllRefs)) = "I am register Y"
+  annotate(AnnotationKey(io.a, JustThisRef)) = "I am io.a"
+  annotate(AnnotationKey(io.bun.nested_1, AllRefs)) = "I am io.bun.nested_1"
+  annotate(AnnotationKey(io.bun.nested_2, JustThisRef)) = "I am io.bun.nested_2"
+}
+
+class AnnotatingExampleTester extends BasicTester {
+  val dut = Module(new AnnotatingExample)
+
+  stop()
+}
+
+class AnnotatingExampleSpec extends FlatSpec with Matchers {
+  behavior of "Annotating components of a circuit"
+
+  it should "contain the following relative keys" in {
+    val annotationMap = MyDriver.buildAnnotatedCircuit { () => new AnnotatingExampleTester }
+
+    annotationMap.contains("SomeSubMod.io.in") should be(true)
+    annotationMap.contains("AnnotatingExample.y") should be(true)
+
+    annotationMap("SomeSubMod.io.in") should be("sub mod io.in")
+  }
+  it should "contain the following absolute keys" in {
+    val annotationMap = MyDriver.buildAnnotatedCircuit { () => new AnnotatingExampleTester }
+
+    annotationMap.contains("AnnotatingExampleTester.dut.subModule2.io.out") should be (true)
+    annotationMap.contains("AnnotatingExampleTester.dut.x") should be (true)
+
+    annotationMap("AnnotatingExampleTester.dut.subModule2.io.out") should be ("sub mod io.out")
+  }
+}
+
+trait AnnotationScope
+case object AllRefs     extends AnnotationScope
+case object JustThisRef extends AnnotationScope
+
+object AnnotationKey {
+  def apply(component: InstanceId): AnnotationKey = {
+    AnnotationKey(component, AllRefs)
+  }
+}
+case class AnnotationKey(val component: InstanceId, scope: AnnotationScope) {
+  override def toString: String = {
+    scope match {
+      case JustThisRef =>
+        s"${component.pathName}"
+      case AllRefs =>
+        s"${component.parentModName}.${component.instanceName}"
+      case  _ =>
+        s"${component.toString}_unknown_scope"
+    }
+  }
+}
+
+class AnnotationMap extends scala.collection.mutable.HashMap[AnnotationKey, String]
+
+class MyDynamicContext {
+  val annotationMap = new AnnotationMap
+}
+
+object MyBuilder {
+  private val myDynamicContextVar = new DynamicVariable[Option[MyDynamicContext]](None)
+
+  def myDynamicContext: MyDynamicContext =
+    myDynamicContextVar.value getOrElse new MyDynamicContext
+
+  def processAnnotations(annotationMap: AnnotationMap): Map[String, String] = {
+    annotationMap.map { case (k,v) => k.toString -> v}.toMap
+  }
+
+  def build[T <: Module](f: => T): Map[String, String] = {
+    myDynamicContextVar.withValue(Some(new MyDynamicContext)) {
+      Driver.emit(() => f)
+      processAnnotations(myDynamicContextVar.value.get.annotationMap)
+    }
+  }
+}
+
+object MyDriver extends BackendCompilationUtilities {
+  /**
+    * illustrates a chisel3 style driver that, annotations can only processed within this structure
+    */
+  def buildAnnotatedCircuit[T <: Module](gen: () => T): Map[String, String] = MyBuilder.build(Module(gen()))
+}
\ No newline at end of file
diff --git a/src/test/scala/chiselTests/Assert.scala b/src/test/scala/chiselTests/Assert.scala
index 24eb8b55..efc2e1e7 100644
--- a/src/test/scala/chiselTests/Assert.scala
+++ b/src/test/scala/chiselTests/Assert.scala
@@ -3,8 +3,9 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class FailingAssertTester() extends BasicTester {
   assert(Bool(false))
@@ -25,7 +26,7 @@ class SucceedingAssertTester() extends BasicTester {
 }
 
 class PipelinedResetModule extends Module {
-  val io = new Bundle { }
+  val io = IO(new Bundle { })
   val a = Reg(init = UInt(0xbeef))
   val b = Reg(init = UInt(0xbeef))
   assert(a === b)
diff --git a/src/test/scala/chiselTests/BetterNamingTests.scala b/src/test/scala/chiselTests/BetterNamingTests.scala
new file mode 100644
index 00000000..f5872adb
--- /dev/null
+++ b/src/test/scala/chiselTests/BetterNamingTests.scala
@@ -0,0 +1,101 @@
+package chiselTests
+
+import org.scalatest.{FlatSpec, Matchers}
+import collection.mutable
+
+import chisel3._
+import chisel3.util._
+
+// Defined outside of the class so we don't get $ in name
+class Other(w: Int) extends Module {
+  val io = new Bundle {
+    val a = UInt(width = w)
+  }
+}
+class PerNameIndexing(count: Int) extends Module {
+  val io = new Bundle { }
+
+  val wires = Seq.tabulate(count) { i => Module(new Other(i)) }
+  val queues = Seq.tabulate(count) { i => Module(new Queue(UInt(width = i), 16)) }
+}
+
+// Note this only checks Iterable[Chisel.Data] which excludes Maps
+class IterableNaming extends Module {
+  val io = new Bundle { }
+
+  val seq = Seq.tabulate(3) { i =>
+    Seq.tabulate(2) { j => Wire(init = (i * j).U) }
+  }
+  val optSet = Some(Set(Wire(init = 0.U),
+                        Wire(init = 1.U),
+                        Wire(init = 2.U),
+                        Wire(init = 3.U)))
+
+  val stack = mutable.Stack[Module]()
+  for (i <- 0 until 4) {
+    stack push Module(new Other(i))
+  }
+
+  def streamFrom(x: Int): Stream[Module] =
+    Module(new Other(x)) #:: streamFrom(x + 1)
+  val stream = streamFrom(0) // Check that we don't get into infinite loop
+  val list = stream.take(8).toList
+}
+
+/* Better Naming Tests
+ *
+ * These tests are intended to validate that Chisel picks better names
+ */
+class BetterNamingTests extends FlatSpec {
+
+  behavior of "Better Naming"
+
+  it should "provide unique counters for each name" in {
+    val verilog = Driver.emit(() => new PerNameIndexing(4))
+    val ModuleDef = """\s*module\s+(\S+)\s+:\s*""".r
+    val expectedModules = Set("PerNameIndexing",
+      "Queue", "Queue_1", "Queue_2", "Queue_3",
+      "Other", "Other_1", "Other_2", "Other_3")
+    val foundModules = for {
+      ModuleDef(name) <- verilog.split("\n").toSeq
+    } yield name
+    assert(foundModules.toSet === expectedModules)
+  }
+
+  it should "provide names for things defined in Iterable[HasId] and Option[HasId]" in {
+    val verilog = Driver.emit(() => new IterableNaming)
+
+    val lines = verilog.split("\n").toSeq
+
+    val SeqDef = """\s*wire\s+seq_(\d+)_(\d+)\s+:\s+UInt\s*""".r
+    val seqs = for {
+      i <- (0 until 3)
+      j <- (0 until 2)
+    } yield (i.toString, j.toString)
+    val foundSeqs = for {
+      SeqDef(i, j) <- lines
+    } yield (i, j)
+    assert(foundSeqs.toSet === seqs.toSet)
+
+    val OptSetDef = """\s*wire\s+optSet_(\d+)\s+:\s+UInt\s*""".r
+    val optSets = (0 until 4) map (_.toString)
+    val foundOptSets = for {
+      OptSetDef(i) <- lines
+    } yield i
+    assert(foundOptSets.toSet === optSets.toSet)
+
+    val StackDef = """\s*inst\s+stack_(\d+)\s+of\s+Other.*""".r
+    val stacks = (0 until 4) map (_.toString)
+    val foundStacks = for {
+      StackDef(i) <- lines
+    } yield i
+    assert(foundStacks.toSet === stacks.toSet)
+
+    val ListDef = """\s*inst\s+list_(\d+)\s+of\s+Other.*""".r
+    val lists = (0 until 8) map (_.toString)
+    val foundLists = for {
+      ListDef(i) <- lines
+    } yield i
+    assert(foundLists.toSet === lists.toSet)
+  }
+}
diff --git a/src/test/scala/chiselTests/BitwiseOps.scala b/src/test/scala/chiselTests/BitwiseOps.scala
index 19aa956c..08999a1b 100644
--- a/src/test/scala/chiselTests/BitwiseOps.scala
+++ b/src/test/scala/chiselTests/BitwiseOps.scala
@@ -2,10 +2,10 @@
 
 package chiselTests
 
-import Chisel._
+import chisel3._
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+import chisel3.testers.BasicTester
 
 class BitwiseOpsTester(w: Int, _a: Int, _b: Int) extends BasicTester {
   val mask = (1 << w) - 1
diff --git a/src/test/scala/chiselTests/BlackBox.scala b/src/test/scala/chiselTests/BlackBox.scala
index ca94087c..344754e1 100644
--- a/src/test/scala/chiselTests/BlackBox.scala
+++ b/src/test/scala/chiselTests/BlackBox.scala
@@ -4,29 +4,32 @@ package chiselTests
 
 import java.io.File
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
+//import chisel3.core.ExplicitCompileOptions.Strict
 
 class BlackBoxInverter extends BlackBox {
-  val io = new Bundle() {
-    val in = Bool(INPUT)
-    val out = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle() {
+    val in = Input(Bool())
+    val out = Output(Bool())
+  })
 }
 
 class BlackBoxPassthrough extends BlackBox {
-  val io = new Bundle() {
-    val in = Bool(INPUT)
-    val out = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle() {
+    val in = Input(Bool())
+    val out = Output(Bool())
+  })
 }
 
 class BlackBoxRegister extends BlackBox {
-  val io = new Bundle() {
-    val clock = Clock().asInput
-    val in = Bool(INPUT)
-    val out = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle() {
+    val clock = Input(Clock())
+    val in = Input(Bool())
+    val out = Output(Bool())
+  })
 }
 
 class BlackBoxTester extends BasicTester {
@@ -84,9 +87,9 @@ class BlackBoxWithClockTester extends BasicTester {
 /*
 // Must determine how to handle parameterized Verilog
 class BlackBoxConstant(value: Int) extends BlackBox {
-  val io = new Bundle() {
-    val out = UInt(width=log2Up(value)).asOutput
-  }
+  val io = IO(new Bundle() {
+    val out = Output(UInt(width=log2Up(value)))
+  })
   override val name = s"#(WIDTH=${log2Up(value)},VALUE=$value) "
 }
 
diff --git a/src/test/scala/chiselTests/BundleWire.scala b/src/test/scala/chiselTests/BundleWire.scala
index 658f5bb9..5b38ff6e 100644
--- a/src/test/scala/chiselTests/BundleWire.scala
+++ b/src/test/scala/chiselTests/BundleWire.scala
@@ -1,21 +1,22 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+import chisel3._
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+import chisel3.testers.BasicTester
+//import chisel3.core.ExplicitCompileOptions.Strict
 
 class Coord extends Bundle {
-  val x = UInt(width = 32)
-  val y = UInt(width = 32)
+  val x = UInt.width( 32)
+  val y = UInt.width( 32)
 }
 
 class BundleWire(n: Int) extends Module {
-  val io = new Bundle {
-    val in   = (new Coord).asInput
-    val outs = Vec(n, new Coord).asOutput
-  }
+  val io = IO(new Bundle {
+    val in   = Input(new Coord)
+    val outs = Output(Vec(n, new Coord))
+  })
   val coords = Wire(Vec(n, new Coord))
   for (i <- 0 until n) {
     coords(i)  := io.in
diff --git a/src/test/scala/chiselTests/ChiselSpec.scala b/src/test/scala/chiselTests/ChiselSpec.scala
index da68b0cb..d335bdf6 100644
--- a/src/test/scala/chiselTests/ChiselSpec.scala
+++ b/src/test/scala/chiselTests/ChiselSpec.scala
@@ -6,8 +6,8 @@ import java.io.File
 import org.scalatest._
 import org.scalatest.prop._
 import org.scalacheck._
-import Chisel._
-import Chisel.testers._
+import chisel3._
+import chisel3.testers._
 
 /** Common utility functions for Chisel unit tests. */
 trait ChiselRunners extends Assertions {
diff --git a/src/test/scala/chiselTests/Clock.scala b/src/test/scala/chiselTests/Clock.scala
new file mode 100644
index 00000000..79dd2de4
--- /dev/null
+++ b/src/test/scala/chiselTests/Clock.scala
@@ -0,0 +1,22 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import org.scalatest._
+import org.scalatest.prop._
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
+
+class ClockAsUIntTester extends BasicTester {
+  assert(Bool(true).asClock.asUInt === UInt(1))
+  stop()
+}
+
+
+class ClockSpec extends ChiselPropSpec {
+  property("Bool.asClock.asUInt should pass a signal through unaltered") {
+    assertTesterPasses { new ClockAsUIntTester }
+  }
+}
diff --git a/src/test/scala/chiselTests/CompileOptionsTest.scala b/src/test/scala/chiselTests/CompileOptionsTest.scala
new file mode 100644
index 00000000..57ceff3f
--- /dev/null
+++ b/src/test/scala/chiselTests/CompileOptionsTest.scala
@@ -0,0 +1,285 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import org.scalatest._
+import chisel3._
+import chisel3.core.Binding.BindingException
+import chisel3.core.ExplicitCompileOptions
+import chisel3.testers.BasicTester
+import chisel3.core.CompileOptions
+
+class CompileOptionsSpec extends ChiselFlatSpec {
+
+  abstract class StrictModule extends Module()(chisel3.core.ExplicitCompileOptions.Strict)
+  abstract class NotStrictModule extends Module()(chisel3.core.ExplicitCompileOptions.NotStrict)
+
+  // Generate a set of options that do not have requireIOWrap enabled, in order to
+  // ensure its definition comes from the implicit options passed to the Module constructor.
+  object StrictWithoutIOWrap extends CompileOptions {
+    val connectFieldsMustMatch = true
+    val declaredTypeMustBeUnbound = true
+    val requireIOWrap = false
+    val dontTryConnectionsSwapped = true
+    val dontAssumeDirectionality = true
+    val deprecateOldDirectionMethods = true
+    val checkSynthesizable = true
+  }
+
+  class SmallBundle extends Bundle {
+    val f1 = UInt(width = 4)
+    val f2 = UInt(width = 5)
+    override def cloneType: this.type = (new SmallBundle).asInstanceOf[this.type]
+  }
+  class BigBundle extends SmallBundle {
+    val f3 = UInt(width = 6)
+    override def cloneType: this.type = (new BigBundle).asInstanceOf[this.type]
+  }
+
+  "A Module with missing bundle fields when compiled with implicit Strict.CompileOption " should "throw an exception" in {
+    a [ChiselException] should be thrownBy {
+      import chisel3.core.ExplicitCompileOptions.Strict
+
+      class ConnectFieldMismatchModule extends Module {
+        val io = IO(new Bundle {
+          val in = Input(new SmallBundle)
+          val out = Output(new BigBundle)
+        })
+        io.out := io.in
+      }
+      elaborate { new ConnectFieldMismatchModule() }
+    }
+  }
+
+  "A Module with missing bundle fields when compiled with implicit NotStrict.CompileOption " should "not throw an exception" in {
+    import chisel3.core.ExplicitCompileOptions.NotStrict
+
+    class ConnectFieldMismatchModule extends Module {
+      val io = IO(new Bundle {
+        val in = Input(new SmallBundle)
+        val out = Output(new BigBundle)
+      })
+      io.out := io.in
+    }
+    elaborate { new ConnectFieldMismatchModule() }
+  }
+
+  "A Module in which a Reg is created with a bound type when compiled with implicit Strict.CompileOption " should "throw an exception" in {
+    a [BindingException] should be thrownBy {
+      import chisel3.core.ExplicitCompileOptions.Strict
+
+      class CreateRegFromBoundTypeModule extends Module {
+        val io = IO(new Bundle {
+          val in = Input(new SmallBundle)
+          val out = Output(new BigBundle)
+        })
+        val badReg = Reg(UInt(7, width=4))
+      }
+      elaborate { new CreateRegFromBoundTypeModule() }
+    }
+  }
+
+  "A Module in which a Reg is created with a bound type when compiled with implicit NotStrict.CompileOption " should "not throw an exception" in {
+    import chisel3.core.ExplicitCompileOptions.NotStrict
+
+    class CreateRegFromBoundTypeModule extends Module {
+      val io = IO(new Bundle {
+        val in = Input(new SmallBundle)
+        val out = Output(new BigBundle)
+      })
+      val badReg = Reg(UInt(7, width=4))
+    }
+    elaborate { new CreateRegFromBoundTypeModule() }
+  }
+
+  "A Module with wrapped IO when compiled with implicit Strict.CompileOption " should "not throw an exception" in {
+    import chisel3.core.ExplicitCompileOptions.Strict
+
+    class RequireIOWrapModule extends Module {
+      val io = IO(new Bundle {
+        val in = UInt(width = 32).asInput
+        val out = Bool().asOutput
+      })
+      io.out := io.in(1)
+    }
+    elaborate { new RequireIOWrapModule() }
+}
+
+  "A Module with unwrapped IO when compiled with implicit NotStrict.CompileOption " should "not throw an exception" in {
+    import chisel3.core.ExplicitCompileOptions.NotStrict
+
+    class RequireIOWrapModule extends Module {
+      val io = new Bundle {
+        val in = UInt(width = 32).asInput
+        val out = Bool().asOutput
+      }
+      io.out := io.in(1)
+    }
+      elaborate { new RequireIOWrapModule() }
+  }
+
+  "A Module with unwrapped IO when compiled with implicit Strict.CompileOption " should "throw an exception" in {
+    a [BindingException] should be thrownBy {
+      import chisel3.core.ExplicitCompileOptions.Strict
+
+      class RequireIOWrapModule extends Module {
+        val io = new Bundle {
+          val in = UInt(width = 32).asInput
+          val out = Bool().asOutput
+        }
+        io.out := io.in(1)
+      }
+      elaborate {
+        new RequireIOWrapModule()
+      }
+    }
+  }
+
+  "A Module connecting output as source to input as sink when compiled with implicit Strict.CompileOption " should "throw an exception" in {
+    a [ChiselException] should be thrownBy {
+      import chisel3.core.ExplicitCompileOptions.Strict
+
+      class SimpleModule extends Module {
+        val io = IO(new Bundle {
+          val in = Input(UInt(width = 3))
+          val out = Output(UInt(width = 4))
+        })
+      }
+      class SwappedConnectionModule extends SimpleModule {
+        val child = Module(new SimpleModule)
+        io.in := child.io.out
+      }
+      elaborate { new SwappedConnectionModule() }
+    }
+  }
+
+  "A Module connecting output as source to input as sink when compiled with implicit NotStrict.CompileOption " should "not throw an exception" in {
+    import chisel3.core.ExplicitCompileOptions.NotStrict
+
+    class SimpleModule extends Module {
+      val io = IO(new Bundle {
+        val in = Input(UInt(width = 3))
+        val out = Output(UInt(width = 4))
+      })
+    }
+    class SwappedConnectionModule extends SimpleModule {
+      val child = Module(new SimpleModule)
+      io.in := child.io.out
+    }
+    elaborate { new SwappedConnectionModule() }
+  }
+
+  "A Module with directionless connections when compiled with implicit Strict.CompileOption " should "throw an exception" in {
+    a [ChiselException] should be thrownBy {
+      // Verify we can suppress the inclusion of default compileOptions
+      import Chisel.{defaultCompileOptions => _, _}
+      import chisel3.core.ExplicitCompileOptions.Strict
+
+      class SimpleModule extends Module {
+        val io = IO(new Bundle {
+          val in = Input(UInt(width = 3))
+          val out = Output(UInt(width = 4))
+        })
+        val noDir = Wire(UInt(width = 3))
+      }
+
+      class DirectionLessConnectionModule extends SimpleModule {
+        val a = UInt(0, width = 3)
+        val b = Wire(UInt(width = 3))
+        val child = Module(new SimpleModule)
+        b := child.noDir
+      }
+      elaborate { new DirectionLessConnectionModule() }
+    }
+  }
+
+  "A Module with directionless connections when compiled with implicit NotStrict.CompileOption " should "not throw an exception" in {
+    import chisel3.core.ExplicitCompileOptions.NotStrict
+
+    class SimpleModule extends Module {
+      val io = IO(new Bundle {
+        val in = Input(UInt(width = 3))
+        val out = Output(UInt(width = 4))
+      })
+      val noDir = Wire(UInt(width = 3))
+    }
+
+    class DirectionLessConnectionModule extends SimpleModule {
+      val a = UInt(0, width = 3)
+      val b = Wire(UInt(width = 3))
+      val child = Module(new SimpleModule)
+      b := child.noDir
+    }
+    elaborate { new DirectionLessConnectionModule() }
+  }
+
+  "A Module with wrapped IO when compiled with explicit Strict.CompileOption " should "not throw an exception" in {
+    implicit val strictWithoutIOWrap = StrictWithoutIOWrap
+    class RequireIOWrapModule extends StrictModule {
+      val io = IO(new Bundle {
+        val in = UInt(width = 32).asInput
+        val out = Bool().asOutput
+      })
+      io.out := io.in(1)
+    }
+    elaborate {
+      new RequireIOWrapModule()
+    }
+  }
+
+  "A Module with unwrapped IO when compiled with explicit NotStrict.CompileOption " should "not throw an exception" in {
+    implicit val strictWithoutIOWrap = StrictWithoutIOWrap
+    class RequireIOWrapModule extends NotStrictModule {
+      val io = new Bundle {
+        val in = UInt(width = 32).asInput
+        val out = Bool().asOutput
+      }
+      io.out := io.in(1)
+    }
+    elaborate {
+      new RequireIOWrapModule()
+    }
+  }
+
+  "A Module with unwrapped IO when compiled with explicit Strict.CompileOption " should "throw an exception" in {
+    a [BindingException] should be thrownBy {
+      implicit val strictWithoutIOWrap = StrictWithoutIOWrap
+      class RequireIOWrapModule extends StrictModule {
+        val io = new Bundle {
+          val in = UInt(width = 32).asInput
+          val out = Bool().asOutput
+        }
+        io.out := io.in(1)
+      }
+      elaborate {
+        new RequireIOWrapModule()
+      }
+    }
+  }
+
+  "A Module with unwrapped IO when compiled with an explicit requireIOWrap false " should "not throw an exception" in {
+
+    object StrictNotIOWrap {
+
+      implicit object CompileOptions extends CompileOptions {
+        val connectFieldsMustMatch = true
+        val declaredTypeMustBeUnbound = true
+        val requireIOWrap = false
+        val dontTryConnectionsSwapped = true
+        val dontAssumeDirectionality = true
+        val deprecateOldDirectionMethods = false
+        val checkSynthesizable = true
+      }
+
+    }
+    class NotIOWrapModule extends Module()(StrictNotIOWrap.CompileOptions) {
+      val io = new Bundle {
+        val in = UInt(width = 32).asInput
+        val out = Bool().asOutput
+      }
+    }
+    elaborate {
+      new NotIOWrapModule()
+    }
+  }
+}
diff --git a/src/test/scala/chiselTests/ComplexAssign.scala b/src/test/scala/chiselTests/ComplexAssign.scala
index d79a2625..0a1f31cc 100644
--- a/src/test/scala/chiselTests/ComplexAssign.scala
+++ b/src/test/scala/chiselTests/ComplexAssign.scala
@@ -1,25 +1,27 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
 import org.scalatest._
 import org.scalatest.prop._
 
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class Complex[T <: Data](val re: T, val im: T) extends Bundle {
   override def cloneType: this.type =
-    new Complex(re.cloneType, im.cloneType).asInstanceOf[this.type]
+    new Complex(re.chiselCloneType, im.chiselCloneType).asInstanceOf[this.type]
 }
 
 class ComplexAssign(w: Int) extends Module {
-  val io = new Bundle {
-    val e   = new Bool(INPUT)
-    val in  = new Complex(UInt(width = w), UInt(width = w)).asInput
-    val out = new Complex(UInt(width = w), UInt(width = w)).asOutput
-  }
+  val io = IO(new Bundle {
+    val e   = Input(Bool())
+    val in  = Input(new Complex(UInt.width(w), UInt.width(w)))
+    val out = Output(new Complex(UInt.width(w), UInt.width(w)))
+  })
   when (io.e) {
-    val tmp = Wire(new Complex(UInt(width = w), UInt(width = w)))
+    val tmp = Wire(new Complex(UInt.width(w), UInt.width(w)))
     tmp := io.in
     io.out.re := tmp.re
     io.out.im := tmp.im
diff --git a/src/test/scala/chiselTests/Counter.scala b/src/test/scala/chiselTests/Counter.scala
index 07a76cdc..69d8a44a 100644
--- a/src/test/scala/chiselTests/Counter.scala
+++ b/src/test/scala/chiselTests/Counter.scala
@@ -1,10 +1,13 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class CountTester(max: Int) extends BasicTester {
   val cnt = Counter(max)
diff --git a/src/test/scala/chiselTests/Decoder.scala b/src/test/scala/chiselTests/Decoder.scala
index e5cdfd07..b50a80c0 100644
--- a/src/test/scala/chiselTests/Decoder.scala
+++ b/src/test/scala/chiselTests/Decoder.scala
@@ -1,17 +1,20 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
 import org.scalatest._
 import org.scalatest.prop._
 import org.scalacheck._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class Decoder(bitpats: List[String]) extends Module {
-  val io = new Bundle {
-    val inst  = UInt(INPUT, 32)
-    val matched = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle {
+    val inst  = Input(UInt.width(32))
+    val matched = Output(Bool())
+  })
   io.matched := Vec(bitpats.map(BitPat(_) === io.inst)).reduce(_||_)
 }
 
diff --git a/src/test/scala/chiselTests/DeqIOSpec.scala b/src/test/scala/chiselTests/DeqIOSpec.scala
index 8f7937ab..d41c50e5 100644
--- a/src/test/scala/chiselTests/DeqIOSpec.scala
+++ b/src/test/scala/chiselTests/DeqIOSpec.scala
@@ -2,8 +2,9 @@
 
 package chiselTests
 
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 /**
   * Created by chick on 2/8/16.
@@ -11,21 +12,21 @@ import Chisel.testers.BasicTester
 class UsesDeqIOInfo extends Bundle {
   val test_width = 32
 
-  val info_data = UInt(width = test_width)
+  val info_data = UInt.width(test_width)
 }
 
 class UsesDeqIO extends Module {
-  val io = new Bundle {
-    val in = new DeqIO(new UsesDeqIOInfo)
-    val out = new EnqIO(new UsesDeqIOInfo)
-  }
+  val io = IO(new Bundle {
+    val in = chisel3.util.DeqIO(new UsesDeqIOInfo)
+    val out = chisel3.util.EnqIO(new UsesDeqIOInfo)
+  })
 }
 
 class DeqIOSpec extends ChiselFlatSpec {
   runTester {
     new BasicTester {
       val dut = new UsesDeqIO
-
+/*
       "DeqIO" should "set the direction of it's parameter to INPUT" in {
         assert(dut.io.in.bits.info_data.dir === INPUT)
       }
@@ -55,6 +56,7 @@ class DeqIOSpec extends ChiselFlatSpec {
         assert(dut.io.out.ready.dir == out_clone.ready.dir)
         assert(dut.io.out.valid.dir == out_clone.valid.dir)
       }
+      */
     }
   }
 }
diff --git a/src/test/scala/chiselTests/Direction.scala b/src/test/scala/chiselTests/Direction.scala
index dd2f6572..949b92ed 100644
--- a/src/test/scala/chiselTests/Direction.scala
+++ b/src/test/scala/chiselTests/Direction.scala
@@ -2,16 +2,16 @@
 
 package chiselTests
 
-import Chisel._
+import chisel3._
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+import chisel3.testers.BasicTester
 
 class DirectionHaver extends Module {
-  val io = new Bundle {
-    val in = UInt(INPUT, 32)
-    val out = UInt(OUTPUT, 32)
-  }
+  val io = IO(new Bundle {
+    val in = Input(UInt.width(32))
+    val out = Output(UInt.width(32))
+  })
 }
 
 class GoodDirection extends DirectionHaver {
@@ -22,7 +22,7 @@ class BadDirection extends DirectionHaver {
   io.in := UInt(0)
 }
 
-class DirectionSpec extends ChiselPropSpec {
+class DirectionSpec extends ChiselPropSpec with ShouldMatchers {
 
   //TODO: In Chisel3 these are actually FIRRTL errors. Remove from tests?
 
@@ -31,7 +31,8 @@ class DirectionSpec extends ChiselPropSpec {
   }
 
   property("Inputs should not be assignable") {
-    elaborate(new BadDirection)
+    a[Exception] should be thrownBy {
+     elaborate(new BadDirection)
+    }
   }
-
 }
diff --git a/src/test/scala/chiselTests/EnableShiftRegister.scala b/src/test/scala/chiselTests/EnableShiftRegister.scala
index 6600df2a..5f3e0dd1 100644
--- a/src/test/scala/chiselTests/EnableShiftRegister.scala
+++ b/src/test/scala/chiselTests/EnableShiftRegister.scala
@@ -1,15 +1,15 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
 
 class EnableShiftRegister extends Module {
-  val io = new Bundle {
-    val in    = UInt(INPUT, 4)
-    val shift = Bool(INPUT)
-    val out   = UInt(OUTPUT, 4)
-  }
+  val io = IO(new Bundle {
+    val in    = Input(UInt.width(4))
+    val shift = Input(Bool())
+    val out   = Output(UInt.width(4))
+  })
   val r0 = Reg(init = UInt(0, 4))
   val r1 = Reg(init = UInt(0, 4))
   val r2 = Reg(init = UInt(0, 4))
diff --git a/src/test/scala/chiselTests/GCD.scala b/src/test/scala/chiselTests/GCD.scala
index a1bfffda..d683ce34 100644
--- a/src/test/scala/chiselTests/GCD.scala
+++ b/src/test/scala/chiselTests/GCD.scala
@@ -2,37 +2,37 @@
 
 package chiselTests
 
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
 import org.scalatest._
 import org.scalatest.prop._
 
 class GCD extends Module {
-  val io = new Bundle {
-    val a  = UInt(INPUT, 32)
-    val b  = UInt(INPUT, 32)
-    val e  = Bool(INPUT)
-    val z  = UInt(OUTPUT, 32)
-    val v  = Bool(OUTPUT)
-  }
-  val x = Reg(UInt(width = 32))
-  val y = Reg(UInt(width = 32))
+  val io = IO(new Bundle {
+    val a  = Input(UInt.width(32))
+    val b  = Input(UInt.width(32))
+    val e  = Input(Bool())
+    val z  = Output(UInt.width(32))
+    val v  = Output(Bool())
+  })
+  val x = Reg(UInt.width( 32))
+  val y = Reg(UInt.width( 32))
   when (x > y)   { x := x -% y }
   .otherwise     { y := y -% x }
   when (io.e) { x := io.a; y := io.b }
   io.z := x
-  io.v := y === UInt(0)
+  io.v := y === 0.U
 }
 
 class GCDTester(a: Int, b: Int, z: Int) extends BasicTester {
   val dut = Module(new GCD)
-  val first = Reg(init=Bool(true))
-  dut.io.a := UInt(a)
-  dut.io.b := UInt(b)
+  val first = Reg(init=true.B)
+  dut.io.a := a.U
+  dut.io.b := b.U
   dut.io.e := first
   when(first) { first := Bool(false) }
-  when(dut.io.v) {
-    assert(dut.io.z === UInt(z))
+  when(!first && dut.io.v) {
+    assert(dut.io.z === z.U)
     stop()
   }
 }
diff --git a/src/test/scala/chiselTests/Harness.scala b/src/test/scala/chiselTests/Harness.scala
index bc838766..83f60391 100644
--- a/src/test/scala/chiselTests/Harness.scala
+++ b/src/test/scala/chiselTests/Harness.scala
@@ -1,13 +1,14 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel.testers.BasicTester
+
+import chisel3.testers.BasicTester
 import org.scalatest._
 import org.scalatest.prop._
 import java.io.File
 
 class HarnessSpec extends ChiselPropSpec
-  with Chisel.BackendCompilationUtilities {
+  with chisel3.BackendCompilationUtilities {
 
   def makeTrivialVerilog: (File => File) = makeHarness((prefix: String) => s"""
 module ${prefix};
diff --git a/src/test/scala/chiselTests/IOCompatibility.scala b/src/test/scala/chiselTests/IOCompatibility.scala
new file mode 100644
index 00000000..7bf3dded
--- /dev/null
+++ b/src/test/scala/chiselTests/IOCompatibility.scala
@@ -0,0 +1,45 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import chisel3._
+
+class IOCSimpleIO extends Bundle {
+  val in  = Input(UInt(width=32))
+  val out = Output(UInt(width=32))
+}
+
+class IOCPlusOne extends Module {
+  val io = IO(new IOCSimpleIO)
+  io.out := io.in + UInt(1)
+}
+
+class IOCModuleVec(val n: Int) extends Module {
+  val io = IO(new Bundle {
+    val ins  = Vec(n, Input(UInt(width=32)))
+    val outs = Vec(n, Output(UInt(width=32)))
+  })
+  val pluses = Vec.fill(n){ Module(new IOCPlusOne).io }
+  for (i <- 0 until n) {
+    pluses(i).in := io.ins(i)
+    io.outs(i)   := pluses(i).out
+  }
+}
+
+class IOCModuleWire extends Module {
+  val io = IO(new IOCSimpleIO)
+  val inc = Wire(Module(new IOCPlusOne).io.chiselCloneType)
+  inc.in := io.in
+  io.out := inc.out
+}
+
+class IOCompatibilitySpec extends ChiselPropSpec {
+
+  property("IOCModuleVec should elaborate") {
+    elaborate { new IOCModuleVec(2) }
+  }
+
+  property("IOCModuleWire should elaborate") {
+    elaborate { new IOCModuleWire }
+  }
+}
diff --git a/src/test/scala/chiselTests/LFSR16.scala b/src/test/scala/chiselTests/LFSR16.scala
index ed76a296..b13b67e3 100644
--- a/src/test/scala/chiselTests/LFSR16.scala
+++ b/src/test/scala/chiselTests/LFSR16.scala
@@ -1,14 +1,16 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class LFSR16 extends Module {
-  val io = new Bundle {
-    val inc = Bool(INPUT)
-    val out = UInt(OUTPUT, 16)
-  }
+  val io = IO(new Bundle {
+    val inc = Input(Bool())
+    val out = Output(UInt.width(16))
+  })
   val res = Reg(init = UInt(1, 16))
   when (io.inc) {
     val nxt_res = Cat(res(0)^res(2)^res(3)^res(5), res(15,1))
@@ -34,7 +36,7 @@ class LFSR16Tester(c: LFSR16) extends Tester(c) {
 }
 */
 
-//TODO: Use chisel.util version instead?
+//TODO: Use chisel3.util version instead?
 
 class LFSRSpec extends ChiselPropSpec {
 
diff --git a/src/test/scala/chiselTests/MemorySearch.scala b/src/test/scala/chiselTests/MemorySearch.scala
index 55b704a0..1d09f3c5 100644
--- a/src/test/scala/chiselTests/MemorySearch.scala
+++ b/src/test/scala/chiselTests/MemorySearch.scala
@@ -1,16 +1,17 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
 
 class MemorySearch extends Module {
-  val io = new Bundle {
-    val target  = UInt(INPUT,  4)
-    val en      = Bool(INPUT)
-    val done    = Bool(OUTPUT)
-    val address = UInt(OUTPUT, 3)
-  }
+  val io = IO(new Bundle {
+    val target  = Input(UInt.width(4))
+    val en      = Input(Bool())
+    val done    = Output(Bool())
+    val address = Output(UInt.width(3))
+  })
   val vals  = Array(0, 4, 15, 14, 2, 5, 13)
   val index = Reg(init = UInt(0, width = 3))
   val elts  = Vec(vals.map(UInt(_,4)))
diff --git a/src/test/scala/chiselTests/Module.scala b/src/test/scala/chiselTests/Module.scala
index 88ba795b..7a4050db 100644
--- a/src/test/scala/chiselTests/Module.scala
+++ b/src/test/scala/chiselTests/Module.scala
@@ -1,23 +1,24 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
+import chisel3._
 
 class SimpleIO extends Bundle {
-  val in  = UInt(INPUT,  32)
-  val out = UInt(OUTPUT, 32)
+  val in  = Input(UInt.width(32))
+  val out = Output(UInt.width(32))
 }
 
 class PlusOne extends Module {
-  val io = new SimpleIO
-  io.out := io.in + UInt(1)
+  val io = IO(new SimpleIO)
+  io.out := io.in + 1.asUInt
 }
 
 class ModuleVec(val n: Int) extends Module {
-  val io = new Bundle {
-    val ins  = Vec(n, UInt(INPUT,  32))
-    val outs = Vec(n, UInt(OUTPUT, 32))
-  }
+  val io = IO(new Bundle {
+    val ins  = Input(Vec(n, UInt(32)))
+    val outs = Output(Vec(n, UInt(32)))
+  })
   val pluses = Vec.fill(n){ Module(new PlusOne).io }
   for (i <- 0 until n) {
     pluses(i).in := io.ins(i)
@@ -39,8 +40,8 @@ class ModuleVecTester(c: ModuleVec) extends Tester(c) {
 */
 
 class ModuleWire extends Module {
-  val io = new SimpleIO
-  val inc = Wire(Module(new PlusOne).io)
+  val io = IO(new SimpleIO)
+  val inc = Wire(Module(new PlusOne).io.chiselCloneType)
   inc.in := io.in
   io.out := inc.out
 }
@@ -57,10 +58,10 @@ class ModuleWireTester(c: ModuleWire) extends Tester(c) {
 */
 
 class ModuleWhen extends Module {
-  val io = new Bundle {
+  val io = IO(new Bundle {
     val s = new SimpleIO
     val en = Bool()
-  }
+  })
   when(io.en) {
     val inc = Module(new PlusOne).io
     inc.in := io.s.in
diff --git a/src/test/scala/chiselTests/ModuleExplicitResetSpec.scala b/src/test/scala/chiselTests/ModuleExplicitResetSpec.scala
new file mode 100644
index 00000000..f8206b9c
--- /dev/null
+++ b/src/test/scala/chiselTests/ModuleExplicitResetSpec.scala
@@ -0,0 +1,38 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+class ModuleExplicitResetSpec extends ChiselFlatSpec  {
+
+  "A Module with an explicit reset in compatibility mode" should "elaborate" in {
+    import Chisel._
+    val myReset = Bool(true)
+    class ModuleExplicitReset(reset: Bool) extends Module(_reset = reset) {
+      val io = new Bundle {
+        val done = Bool(OUTPUT)
+      }
+
+      io.done := Bool(false)
+    }
+
+    elaborate {
+      new ModuleExplicitReset(myReset)
+    }
+  }
+
+  "A Module with an explicit reset in non-compatibility mode" should "elaborate" in {
+    import chisel3._
+    val myReset = Bool(true)
+    class ModuleExplicitReset(reset: Bool) extends Module(_reset = reset) {
+      val io = IO(new Bundle {
+        val done = Bool(OUTPUT)
+      })
+
+      io.done := Bool(false)
+    }
+
+    elaborate {
+      new ModuleExplicitReset(myReset)
+    }
+  }
+}
diff --git a/src/test/scala/chiselTests/MulLookup.scala b/src/test/scala/chiselTests/MulLookup.scala
index 49ba13c7..26ee4e03 100644
--- a/src/test/scala/chiselTests/MulLookup.scala
+++ b/src/test/scala/chiselTests/MulLookup.scala
@@ -2,17 +2,17 @@
 
 package chiselTests
 
-import Chisel._
+import chisel3._
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+import chisel3.testers.BasicTester
 
 class MulLookup(val w: Int) extends Module {
-  val io = new Bundle {
-    val x   = UInt(INPUT,  w)
-    val y   = UInt(INPUT,  w)
-    val z   = UInt(OUTPUT, 2 * w)
-  }
+  val io = IO(new Bundle {
+    val x   = Input(UInt.width(w))
+    val y   = Input(UInt.width(w))
+    val z   = Output(UInt.width(2 * w))
+  })
   val tbl = Vec(
     for {
       i <- 0 until 1 << w
diff --git a/src/test/scala/chiselTests/MultiAssign.scala b/src/test/scala/chiselTests/MultiAssign.scala
index 2f464123..fa4c4898 100644
--- a/src/test/scala/chiselTests/MultiAssign.scala
+++ b/src/test/scala/chiselTests/MultiAssign.scala
@@ -3,36 +3,43 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class LastAssignTester() extends BasicTester {
   val cnt = Counter(2)
 
-  val test = Wire(UInt(width=4))
-  assert(test === UInt(7))  // allow read references before assign references
+  val test = Wire(UInt.width(4))
+  assert(test === 7.U)  // allow read references before assign references
 
-  test := UInt(13)
-  assert(test === UInt(7))  // output value should be position-independent
+  test := 13.U
+  assert(test === 7.U)  // output value should be position-independent
 
-  test := UInt(7)
-  assert(test === UInt(7))  // this obviously should work
+  test := 7.U
+  assert(test === 7.U)  // this obviously should work
 
-  when(cnt.value === UInt(1)) {
+  when(cnt.value === 1.U) {
     stop()
   }
 }
 
 class ReassignmentTester() extends BasicTester {
-  val test = UInt(15)
-  test := UInt(7)
+  val test = 15.U
+  test := 7.U
 }
 
 class MultiAssignSpec extends ChiselFlatSpec {
   "The last assignment" should "be used when multiple assignments happen" in {
     assertTesterPasses{ new LastAssignTester }
   }
+}
+
+class IllegalAssignSpec extends ChiselFlatSpec {
   "Reassignments to non-wire types" should "be disallowed" in {
-    assertTesterFails{ new ReassignmentTester }
+    intercept[chisel3.internal.ChiselException] {
+      assertTesterFails{ new ReassignmentTester }
+    }
   }
 }
diff --git a/src/test/scala/chiselTests/OptionBundle.scala b/src/test/scala/chiselTests/OptionBundle.scala
index c5a347e6..8e4c7579 100644
--- a/src/test/scala/chiselTests/OptionBundle.scala
+++ b/src/test/scala/chiselTests/OptionBundle.scala
@@ -3,20 +3,20 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
 
 class OptionBundle(hasIn: Boolean) extends Bundle {
   val in = if (hasIn) {
-    Some(Bool(INPUT))
+    Some(Input(Bool()))
   } else {
     None
   }
-  val out = Bool(OUTPUT)
+  val out = Output(Bool())
 }
 
 class OptionBundleModule(hasIn: Boolean) extends Module {
-  val io = new OptionBundle(hasIn)
+  val io = IO(new OptionBundle(hasIn))
   if (hasIn) {
     io.out := io.in.get
   } else {
diff --git a/src/test/scala/chiselTests/Padding.scala b/src/test/scala/chiselTests/Padding.scala
index 999b7d36..42df6802 100644
--- a/src/test/scala/chiselTests/Padding.scala
+++ b/src/test/scala/chiselTests/Padding.scala
@@ -1,14 +1,15 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
+import chisel3._
 
 class Padder extends Module {
-  val io = new Bundle {
-    val a   = Bits(INPUT,  4)
-    val asp = SInt(OUTPUT, 8)
-    val aup = UInt(OUTPUT, 8)
-  }
+  val io = IO(new Bundle {
+    val a   = Input(UInt.width(4))
+    val asp = Output(SInt.width(8))
+    val aup = Output(UInt.width(8))
+  })
   io.asp := io.a.asSInt
   io.aup := io.a.asUInt
 }
diff --git a/src/test/scala/chiselTests/ParameterizedModule.scala b/src/test/scala/chiselTests/ParameterizedModule.scala
index 35e3ba78..14b21631 100644
--- a/src/test/scala/chiselTests/ParameterizedModule.scala
+++ b/src/test/scala/chiselTests/ParameterizedModule.scala
@@ -3,14 +3,14 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
 
 class ParameterizedModule(invert: Boolean) extends Module {
-  val io = new Bundle {
-    val in = new Bool(INPUT)
-    val out = new Bool(OUTPUT)
-  }
+  val io = IO(new Bundle {
+    val in  = Input(Bool())
+    val out = Output(Bool())
+  })
   if (invert) {
     io.out := !io.in
   } else {
diff --git a/src/test/scala/chiselTests/PrintableSpec.scala b/src/test/scala/chiselTests/PrintableSpec.scala
new file mode 100644
index 00000000..12564a40
--- /dev/null
+++ b/src/test/scala/chiselTests/PrintableSpec.scala
@@ -0,0 +1,187 @@
+package chiselTests
+
+import org.scalatest.{FlatSpec, Matchers}
+import scala.collection.mutable
+
+import chisel3._
+import chisel3.testers.BasicTester
+
+/* Printable Tests */
+class PrintableSpec extends FlatSpec with Matchers {
+  private val PrintfRegex = """\s*printf\((.*)\).*""".r
+  // This regex is brittle, it relies on the first two arguments of the printf
+  // not containing quotes, problematic if Chisel were to emit UInt<1>("h01")
+  // instead of the current UInt<1>(1) for the enable signal
+  private val StringRegex = """([^"]*)"(.*?)"(.*)""".r
+  private case class Printf(str: String, args: Seq[String])
+  private def getPrintfs(firrtl: String): Seq[Printf] = {
+    def processArgs(str: String): Seq[String] =
+      str split "," map (_.trim) filter (_.nonEmpty)
+    def processBody(str: String): (String, Seq[String]) = {
+      str match {
+        case StringRegex(_, fmt, args) =>
+          (fmt, processArgs(args))
+        case _ => fail(s"Regex to process Printf should work on $str!")
+      }
+    }
+
+    firrtl split "\n" collect {
+      case PrintfRegex(matched) =>
+        val (str, args) = processBody(matched)
+        Printf(str, args)
+    }
+  }
+
+  behavior of "Printable & Custom Interpolator"
+
+  it should "pass exact strings through" in {
+    class MyModule extends BasicTester {
+      printf(p"An exact string")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("An exact string", Seq())) =>
+      case e => fail()
+    }
+  }
+  it should "handle Printable and String concatination" in {
+    class MyModule extends BasicTester {
+      printf(p"First " + PString("Second ") + "Third")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("First Second Third", Seq())) =>
+      case e => fail()
+    }
+  }
+  it should "call toString on non-Printable objects" in {
+    class MyModule extends BasicTester {
+      val myInt = 1234
+      printf(p"myInt = $myInt")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("myInt = 1234", Seq())) =>
+      case e => fail()
+    }
+  }
+  it should "generate proper printf for simple Decimal printing" in {
+    class MyModule extends BasicTester {
+      val myWire = Wire(init = UInt(1234))
+      printf(p"myWire = ${Decimal(myWire)}")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("myWire = %d", Seq("myWire"))) =>
+      case e => fail()
+    }
+  }
+  it should "handle printing literals" in {
+    class MyModule extends BasicTester {
+      printf(Decimal(UInt(10, 32)))
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("%d", Seq(lit))) =>
+        assert(lit contains "UInt<32>")
+      case e => fail()
+    }
+  }
+  it should "correctly escape percent" in {
+    class MyModule extends BasicTester {
+      printf(p"%")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("%%", Seq())) =>
+      case e => fail()
+    }
+  }
+  it should "support names of circuit elements including submodule IO" in {
+    // Submodule IO is a subtle issue because the Chisel element has a different
+    // parent module
+    class MySubModule extends Module {
+      val io = new Bundle {
+        val fizz = UInt(width = 32)
+      }
+    }
+    class MyBundle extends Bundle {
+      val foo = UInt(width = 32)
+      override def cloneType = (new MyBundle).asInstanceOf[this.type]
+    }
+    class MyModule extends BasicTester {
+      override def desiredName = "MyModule"
+      val myWire = Wire(new MyBundle)
+      val myInst = Module(new MySubModule)
+      printf(p"${Name(myWire.foo)}")
+      printf(p"${FullName(myWire.foo)}")
+      printf(p"${FullName(myInst.io.fizz)}")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    println(firrtl)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("foo", Seq()),
+               Printf("myWire.foo", Seq()),
+               Printf("myInst.io.fizz", Seq())) =>
+      case e => fail()
+    }
+  }
+  it should "handle printing ports of submodules" in {
+    class MySubModule extends Module {
+      val io = new Bundle {
+        val fizz = UInt(width = 32)
+      }
+    }
+    class MyModule extends BasicTester {
+      val myInst = Module(new MySubModule)
+      printf(p"${myInst.io.fizz}")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("%d", Seq("myInst.io.fizz"))) =>
+      case e => fail()
+    }
+  }
+  it should "print UInts and SInts as Decimal by default" in {
+    class MyModule extends BasicTester {
+      val myUInt = Wire(init = UInt(0))
+      val mySInt = Wire(init = SInt(-1))
+      printf(p"$myUInt & $mySInt")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("%d & %d", Seq("myUInt", "mySInt"))) =>
+      case e => fail()
+    }
+  }
+  it should "print Vecs like Scala Seqs by default" in {
+    class MyModule extends BasicTester {
+      val myVec = Wire(Vec(4, UInt(width = 32)))
+      myVec foreach (_ := UInt(0))
+      printf(p"$myVec")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("Vec(%d, %d, %d, %d)",
+               Seq("myVec[0]", "myVec[1]", "myVec[2]", "myVec[3]"))) =>
+      case e => fail()
+    }
+  }
+  it should "print Bundles like Scala Maps by default" in {
+    class MyModule extends BasicTester {
+      val myBun = Wire(new Bundle {
+        val foo = UInt(width = 32)
+        val bar = UInt(width = 32)
+      })
+      myBun.foo := UInt(0)
+      myBun.bar := UInt(0)
+      printf(p"$myBun")
+    }
+    val firrtl = Driver.emit(() => new MyModule)
+    getPrintfs(firrtl) match {
+      case Seq(Printf("Bundle(foo -> %d, bar -> %d)",
+               Seq("myBun.foo", "myBun.bar"))) =>
+      case e => fail()
+    }
+  }
+}
diff --git a/src/test/scala/chiselTests/Printf.scala b/src/test/scala/chiselTests/Printf.scala
index eb8b4b25..28b6132b 100644
--- a/src/test/scala/chiselTests/Printf.scala
+++ b/src/test/scala/chiselTests/Printf.scala
@@ -3,8 +3,9 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.util._
+import chisel3.testers.BasicTester
 
 class SinglePrintfTester() extends BasicTester {
   val x = UInt(254)
@@ -24,6 +25,11 @@ class MultiPrintfTester() extends BasicTester {
   stop()
 }
 
+class ASCIIPrintableTester extends BasicTester {
+  printf(PString((0x20 to 0x7e) map (_.toChar) mkString ""))
+  stop()
+}
+
 class PrintfSpec extends ChiselFlatSpec {
   "A printf with a single argument" should "run" in {
     assertTesterPasses { new SinglePrintfTester }
@@ -34,4 +40,7 @@ class PrintfSpec extends ChiselFlatSpec {
   "A printf with ASCII characters 1-127" should "run" in {
     assertTesterPasses { new ASCIIPrintfTester }
   }
+  "A printf with Printable ASCII characters 1-127" should "run" in {
+    assertTesterPasses { new ASCIIPrintableTester }
+  }
 }
diff --git a/src/test/scala/chiselTests/Reg.scala b/src/test/scala/chiselTests/Reg.scala
index f2620d88..a9086223 100644
--- a/src/test/scala/chiselTests/Reg.scala
+++ b/src/test/scala/chiselTests/Reg.scala
@@ -3,8 +3,9 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.core.DataMirror
+import chisel3.testers.BasicTester
 
 class RegSpec extends ChiselFlatSpec {
   "A Reg" should "throw an exception if not given any parameters" in {
@@ -15,20 +16,23 @@ class RegSpec extends ChiselFlatSpec {
 
   "A Reg" should "be of the same type and width as outType, if specified" in {
     class RegOutTypeWidthTester extends BasicTester {
-      val reg = Reg(t=UInt(width=2), next=UInt(width=3), init=UInt(20))
-      reg.width.get should be (2)
+      val reg = Reg(t=UInt(width=2), next=Wire(UInt(width=3)), init=UInt(20))
+      reg.getWidth should be (2)
     }
     elaborate{ new RegOutTypeWidthTester }
   }
 
   "A Reg" should "be of unknown width if outType is not specified and width is not forced" in {
     class RegUnknownWidthTester extends BasicTester {
-      val reg1 = Reg(next=UInt(width=3), init=UInt(20))
-      reg1.width.known should be (false)
+      val reg1 = Reg(next=Wire(UInt(width=3)), init=UInt(20))
+      reg1.isWidthKnown should be (false)
+      DataMirror.widthOf(reg1).known should be (false)
       val reg2 = Reg(init=UInt(20))
-      reg2.width.known should be (false)
-      val reg3 = Reg(next=UInt(width=3), init=UInt(width=5))
-      reg3.width.known should be (false)
+      reg2.isWidthKnown should be (false)
+      DataMirror.widthOf(reg2).known should be (false)
+      val reg3 = Reg(next=Wire(UInt(width=3)), init=UInt(5))
+      reg3.isWidthKnown should be (false)
+      DataMirror.widthOf(reg3).known should be (false)
     }
     elaborate { new RegUnknownWidthTester }
   }
@@ -36,7 +40,7 @@ class RegSpec extends ChiselFlatSpec {
   "A Reg" should "be of width of init if outType and next are missing and init is a literal of forced width" in {
     class RegForcedWidthTester extends BasicTester {
       val reg2 = Reg(init=UInt(20, width=7))
-      reg2.width.get should be (7)
+      reg2.getWidth should be (7)
     }
     elaborate{ new RegForcedWidthTester }
   }
diff --git a/src/test/scala/chiselTests/Risc.scala b/src/test/scala/chiselTests/Risc.scala
index 3daa5bd2..6d5a0a76 100644
--- a/src/test/scala/chiselTests/Risc.scala
+++ b/src/test/scala/chiselTests/Risc.scala
@@ -1,23 +1,25 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
+import chisel3._
+import chisel3.util._
 
 class Risc extends Module {
-  val io = new Bundle {
-    val isWr   = Bool(INPUT)
-    val wrAddr = UInt(INPUT, 8)
-    val wrData = Bits(INPUT, 32)
-    val boot   = Bool(INPUT)
-    val valid  = Bool(OUTPUT)
-    val out    = Bits(OUTPUT, 32)
-  }
+  val io = IO(new Bundle {
+    val isWr   = Input(Bool())
+    val wrAddr = Input(UInt.width(8))
+    val wrData = Input(Bits.width(32))
+    val boot   = Input(Bool())
+    val valid  = Output(Bool())
+    val out    = Output(Bits.width(32))
+  })
   val memSize = 256
-  val file = Mem(memSize, Bits(width = 32))
-  val code = Mem(memSize, Bits(width = 32))
+  val file = Mem(memSize, Bits.width(32))
+  val code = Mem(memSize, Bits.width(32))
   val pc   = Reg(init=UInt(0, 8))
 
-  val add_op :: imm_op :: Nil = Enum(Bits(width = 8), 2)
+  val add_op :: imm_op :: Nil = Enum(Bits.width(8), 2)
 
   val inst = code(pc)
   val op   = inst(31,24)
@@ -25,13 +27,13 @@ class Risc extends Module {
   val rai  = inst(15, 8)
   val rbi  = inst( 7, 0)
 
-  val ra = Mux(rai === Bits(0), Bits(0), file(rai))
-  val rb = Mux(rbi === Bits(0), Bits(0), file(rbi))
-  val rc = Wire(Bits(width = 32))
+  val ra = Mux(rai === 0.asUInt(), 0.asUInt(), file(rai))
+  val rb = Mux(rbi === 0.asUInt(), 0.asUInt(), file(rbi))
+  val rc = Wire(Bits.width(32))
 
   io.valid := Bool(false)
-  io.out   := Bits(0)
-  rc       := Bits(0)
+  io.out   := 0.asUInt()
+  rc       := 0.asUInt()
 
   when (io.isWr) {
     code(io.wrAddr) := io.wrData
@@ -43,12 +45,12 @@ class Risc extends Module {
       is(imm_op) { rc := (rai << 8) | rbi }
     }
     io.out := rc
-    when (rci === UInt(255)) {
+    when (rci === 255.asUInt()) {
       io.valid := Bool(true)
     } .otherwise {
       file(rci) := rc
     }
-    pc := pc +% UInt(1)
+    pc := pc +% 1.asUInt()
   }
 }
 
diff --git a/src/test/scala/chiselTests/SIntOps.scala b/src/test/scala/chiselTests/SIntOps.scala
index 0835fb4d..392c4803 100644
--- a/src/test/scala/chiselTests/SIntOps.scala
+++ b/src/test/scala/chiselTests/SIntOps.scala
@@ -1,28 +1,29 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
 
 class SIntOps extends Module {
-  val io = new Bundle {
-    val a = SInt(INPUT, 16)
-    val b = SInt(INPUT, 16)
-    val addout = SInt(OUTPUT, 16)
-    val subout = SInt(OUTPUT, 16)
-    val timesout = SInt(OUTPUT, 16)
-    val divout = SInt(OUTPUT, 16)
-    val modout = SInt(OUTPUT, 16)
-    val lshiftout = SInt(OUTPUT, 16)
-    val rshiftout = SInt(OUTPUT, 16)
-    val lessout = Bool(OUTPUT)
-    val greatout = Bool(OUTPUT)
-    val eqout = Bool(OUTPUT)
-    val noteqout = Bool(OUTPUT)
-    val lesseqout = Bool(OUTPUT)
-    val greateqout = Bool(OUTPUT)
-    val negout = SInt(OUTPUT, 16)
-  }
+  val io = IO(new Bundle {
+    val a = Input(SInt.width(16))
+    val b = Input(SInt.width(16))
+    val addout = Output(SInt.width(16))
+    val subout = Output(SInt.width(16))
+    val timesout = Output(SInt.width(16))
+    val divout = Output(SInt.width(16))
+    val modout = Output(SInt.width(16))
+    val lshiftout = Output(SInt.width(16))
+    val rshiftout = Output(SInt.width(16))
+    val lessout = Output(Bool())
+    val greatout = Output(Bool())
+    val eqout = Output(Bool())
+    val noteqout = Output(Bool())
+    val lesseqout = Output(Bool())
+    val greateqout = Output(Bool())
+    val negout = Output(SInt.width(16))
+  })
 
   val a = io.a
   val b = io.b
diff --git a/src/test/scala/chiselTests/Stack.scala b/src/test/scala/chiselTests/Stack.scala
index ac799c8a..a72af928 100644
--- a/src/test/scala/chiselTests/Stack.scala
+++ b/src/test/scala/chiselTests/Stack.scala
@@ -1,19 +1,22 @@
 // See LICENSE for license details.
 
 package chiselTests
+
 import scala.collection.mutable.Stack
-import Chisel._
+
+import chisel3._
+import chisel3.util._
 
 class ChiselStack(val depth: Int) extends Module {
-  val io = new Bundle {
-    val push    = Bool(INPUT)
-    val pop     = Bool(INPUT)
-    val en      = Bool(INPUT)
-    val dataIn  = UInt(INPUT,  32)
-    val dataOut = UInt(OUTPUT, 32)
-  }
+  val io = IO(new Bundle {
+    val push    = Input(Bool())
+    val pop     = Input(Bool())
+    val en      = Input(Bool())
+    val dataIn  = Input(UInt.width(32))
+    val dataOut = Output(UInt.width(32))
+  })
 
-  val stack_mem = Mem(depth, UInt(width = 32))
+  val stack_mem = Mem(depth, UInt.width(32))
   val sp        = Reg(init = UInt(0, width = log2Up(depth + 1)))
   val out       = Reg(init = UInt(0, width = 32))
 
diff --git a/src/test/scala/chiselTests/Stop.scala b/src/test/scala/chiselTests/Stop.scala
index 878f090c..4afb077a 100644
--- a/src/test/scala/chiselTests/Stop.scala
+++ b/src/test/scala/chiselTests/Stop.scala
@@ -3,8 +3,8 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
 
 class StopTester() extends BasicTester {
   stop()
diff --git a/src/test/scala/chiselTests/Tbl.scala b/src/test/scala/chiselTests/Tbl.scala
index c79eb8a4..66a06435 100644
--- a/src/test/scala/chiselTests/Tbl.scala
+++ b/src/test/scala/chiselTests/Tbl.scala
@@ -2,20 +2,22 @@
 
 package chiselTests
 
-import Chisel._
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 class Tbl(w: Int, n: Int) extends Module {
-  val io = new Bundle {
-    val wi  = UInt(INPUT, log2Up(n))
-    val ri  = UInt(INPUT, log2Up(n))
-    val we  = Bool(INPUT)
-    val  d  = UInt(INPUT, w)
-    val  o  = UInt(OUTPUT, w)
-  }
-  val m = Mem(n, UInt(width = w))
+  val io = IO(new Bundle {
+    val wi  = Input(UInt.width(log2Up(n)))
+    val ri  = Input(UInt.width(log2Up(n)))
+    val we  = Input(Bool())
+    val  d  = Input(UInt.width(w))
+    val  o  = Output(UInt.width(w))
+  })
+  val m = Mem(n, UInt.width(w))
   io.o := m(io.ri)
   when (io.we) {
     m(io.wi) := io.d
diff --git a/src/test/scala/chiselTests/TesterDriverSpec.scala b/src/test/scala/chiselTests/TesterDriverSpec.scala
index 3c57daae..b2e811d9 100644
--- a/src/test/scala/chiselTests/TesterDriverSpec.scala
+++ b/src/test/scala/chiselTests/TesterDriverSpec.scala
@@ -2,8 +2,10 @@
 
 package chiselTests
 
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
+//import chisel3.core.ExplicitCompileOptions.Strict
 
 /** Extend BasicTester with a simple circuit and finish method.  TesterDriver will call the
   * finish method after the FinishTester's constructor has completed, which will alter the
@@ -19,7 +21,7 @@ class FinishTester extends BasicTester {
     stop()
   }
 
-  val test_wire = Wire(UInt(1, width = test_wire_width))
+  val test_wire = Wire(init=UInt(1, test_wire_width))
 
   // though we just set test_wire to 1, the assert below will pass because
   // the finish will change its value
diff --git a/src/test/scala/chiselTests/UIntOps.scala b/src/test/scala/chiselTests/UIntOps.scala
index bb0b0f06..ad5aecd8 100644
--- a/src/test/scala/chiselTests/UIntOps.scala
+++ b/src/test/scala/chiselTests/UIntOps.scala
@@ -1,28 +1,29 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
+import chisel3._
 import org.scalatest._
-import Chisel.testers.BasicTester
+import chisel3.testers.BasicTester
 
 class UIntOps extends Module {
-  val io = new Bundle {
-    val a = UInt(INPUT, 16)
-    val b = UInt(INPUT, 16)
-    val addout = UInt(OUTPUT, 16)
-    val subout = UInt(OUTPUT, 16)
-    val timesout = UInt(OUTPUT, 16)
-    val divout = UInt(OUTPUT, 16)
-    val modout = UInt(OUTPUT, 16)
-    val lshiftout = UInt(OUTPUT, 16)
-    val rshiftout = UInt(OUTPUT, 16)
-    val lessout = Bool(OUTPUT)
-    val greatout = Bool(OUTPUT)
-    val eqout = Bool(OUTPUT)
-    val noteqout = Bool(OUTPUT)
-    val lesseqout = Bool(OUTPUT)
-    val greateqout = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle {
+    val a = Input(UInt.width(16))
+    val b = Input(UInt.width(16))
+    val addout = Output(UInt.width(16))
+    val subout = Output(UInt.width(16))
+    val timesout = Output(UInt.width(16))
+    val divout = Output(UInt.width(16))
+    val modout = Output(UInt.width(16))
+    val lshiftout = Output(UInt.width(16))
+    val rshiftout = Output(UInt.width(16))
+    val lessout = Output(Bool())
+    val greatout = Output(Bool())
+    val eqout = Output(Bool())
+    val noteqout = Output(Bool())
+    val lesseqout = Output(Bool())
+    val greateqout = Output(Bool())
+  })
 
   val a = io.a
   val b = io.b
@@ -76,18 +77,18 @@ class UIntOpsTester(c: UIntOps) extends Tester(c) {
 */
 
 class GoodBoolConversion extends Module {
-  val io = new Bundle {
-    val u = UInt(1, width = 1).asInput
-    val b = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle {
+    val u = Input(UInt.width(1))
+    val b = Output(Bool())
+  })
   io.b := io.u.toBool
 }
 
 class BadBoolConversion extends Module {
-  val io = new Bundle {
-    val u = UInt(1, width = 5).asInput
-    val b = Bool(OUTPUT)
-  }
+  val io = IO(new Bundle {
+    val u = Input(UInt.width( 5))
+    val b = Output(Bool())
+  })
   io.b := io.u.toBool
 }
 
diff --git a/src/test/scala/chiselTests/Vec.scala b/src/test/scala/chiselTests/Vec.scala
index 9ff8ed46..0d5a2188 100644
--- a/src/test/scala/chiselTests/Vec.scala
+++ b/src/test/scala/chiselTests/Vec.scala
@@ -2,10 +2,13 @@
 
 package chiselTests
 
-import Chisel._
 import org.scalatest._
 import org.scalatest.prop._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
+//import chisel3.core.ExplicitCompileOptions.Strict
 
 class ValueTester(w: Int, values: List[Int]) extends BasicTester {
   val v = Vec(values.map(UInt(_, width = w))) // TODO: does this need a Wire? Why no error?
@@ -29,7 +32,7 @@ class TabulateTester(n: Int) extends BasicTester {
 
 class ShiftRegisterTester(n: Int) extends BasicTester {
   val (cnt, wrap) = Counter(Bool(true), n*2)
-  val shifter = Reg(Vec(n, UInt(width = log2Up(n))))
+  val shifter = Reg(Vec(n, UInt.width(log2Up(n))))
   (shifter, shifter drop 1).zipped.foreach(_ := _)
   shifter(n-1) := cnt
   when (cnt >= UInt(n)) {
@@ -41,32 +44,6 @@ class ShiftRegisterTester(n: Int) extends BasicTester {
   }
 }
 
-class FunBundle extends Bundle {
-  val stuff = UInt(width = 10)
-}
-
-class ZeroModule extends Module {
-  val io = new Bundle {
-    val mem = UInt(width = 10)
-    val interrupts = Vec(2, Bool()).asInput
-    val mmio_axi = Vec(0, new FunBundle)
-    val mmio_ahb = Vec(0, new FunBundle).flip
-  }
-  
-  io.mmio_axi <> io.mmio_ahb
-  
-  io.mem := UInt(0)
-  when (io.interrupts(0)) { io.mem := UInt(1) }
-  when (io.interrupts(1)) { io.mem := UInt(2) }
-}
-
-class ZeroTester extends BasicTester {
-  val foo = Module(new ZeroModule)
-  foo.io.interrupts := Vec.tabulate(2) { _ => Bool(true) }
-  assert (foo.io.mem === UInt(2))
-  stop()
-}
-
 class VecSpec extends ChiselPropSpec {
   property("Vecs should be assignable") {
     forAll(safeUIntN(8)) { case(w: Int, v: List[Int]) =>
@@ -81,8 +58,4 @@ class VecSpec extends ChiselPropSpec {
   property("Regs of vecs should be usable as shift registers") {
     forAll(smallPosInts) { (n: Int) => assertTesterPasses{ new ShiftRegisterTester(n) } }
   }
-  
-  property("Dual empty Vectors") {
-    assertTesterPasses{ new ZeroTester }
-  }
 }
diff --git a/src/test/scala/chiselTests/VectorPacketIO.scala b/src/test/scala/chiselTests/VectorPacketIO.scala
index 99ec66a6..b8e3a154 100644
--- a/src/test/scala/chiselTests/VectorPacketIO.scala
+++ b/src/test/scala/chiselTests/VectorPacketIO.scala
@@ -2,8 +2,9 @@
 
 package chiselTests
 
-import Chisel._
-import Chisel.testers.BasicTester
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
 
 /**
   * This test used to fail when assignment statements were
@@ -18,7 +19,7 @@ import Chisel.testers.BasicTester
   * IMPORTANT:  The canonical way to initialize a decoupled inteface is still being debated.
   */
 class Packet extends Bundle {
-  val header = UInt(width = 1)
+  val header = UInt.width(1)
 }
 
 /**
@@ -27,8 +28,8 @@ class Packet extends Bundle {
   * The problem does not occur if the Vec is taken out
   */
 class VectorPacketIO(n: Int) extends Bundle {
-  val ins  = Vec(n, new DeqIO(new Packet()))
-  val outs = Vec(n, new EnqIO(new Packet()))
+  val ins  = Vec(n, chisel3.util.DeqIO(new Packet()))
+  val outs = Vec(n, chisel3.util.EnqIO(new Packet()))
 }
 
 /**
@@ -37,10 +38,11 @@ class VectorPacketIO(n: Int) extends Bundle {
   */
 class BrokenVectorPacketModule extends Module {
   val n  = 4
-  val io = new VectorPacketIO(n)
+  val io = IO(new VectorPacketIO(n))
 
   /* the following method of initializing the circuit may change in the future */
-  io.outs.foreach(_.init())
+  io.ins.foreach(_.nodeq())
+  io.outs.foreach(_.noenq())
 }
 
 class VectorPacketIOUnitTester extends BasicTester {
diff --git a/src/test/scala/chiselTests/VendingMachine.scala b/src/test/scala/chiselTests/VendingMachine.scala
index 012fc493..00b1e7de 100644
--- a/src/test/scala/chiselTests/VendingMachine.scala
+++ b/src/test/scala/chiselTests/VendingMachine.scala
@@ -1,13 +1,16 @@
 // See LICENSE for license details.
 
 package chiselTests
-import Chisel._
+
+import chisel3._
+import chisel3.util._
 
 class VendingMachine extends Module {
-  val io = new Bundle {
-    val nickel = Bool(dir = INPUT)
-    val dime   = Bool(dir = INPUT)
-    val valid  = Bool(dir = OUTPUT) }
+  val io = IO(new Bundle {
+    val nickel = Input(Bool())
+    val dime   = Input(Bool())
+    val valid  = Output(Bool())
+  })
   val c = UInt(5, width = 3)
   val sIdle :: s5 :: s10 :: s15 :: sOk :: Nil = Enum(UInt(), 5)
   val state = Reg(init = sIdle)
diff --git a/src/test/scala/chiselTests/When.scala b/src/test/scala/chiselTests/When.scala
index a6572706..6dc2dbac 100644
--- a/src/test/scala/chiselTests/When.scala
+++ b/src/test/scala/chiselTests/When.scala
@@ -3,14 +3,17 @@
 package chiselTests
 
 import org.scalatest._
-import Chisel._
-import Chisel.testers.BasicTester
+
+import chisel3._
+import chisel3.testers.BasicTester
+import chisel3.util._
+//import chisel3.core.ExplicitCompileOptions.Strict
 
 class WhenTester() extends BasicTester {
   val cnt = Counter(4)
   when(Bool(true)) { cnt.inc() }
 
-  val out = Wire(UInt(width=3))
+  val out = Wire(UInt.width(3))
   when(cnt.value === UInt(0)) {
     out := UInt(1)
   } .elsewhen (cnt.value === UInt(1)) {
@@ -32,7 +35,7 @@ class OverlappedWhenTester() extends BasicTester {
   val cnt = Counter(4)
   when(Bool(true)) { cnt.inc() }
 
-  val out = Wire(UInt(width=3))
+  val out = Wire(UInt.width(3))
   when(cnt.value <= UInt(0)) {
     out := UInt(1)
   } .elsewhen (cnt.value <= UInt(1)) {